FOAM SEPARATION CLARIFICATION OF NATURAL WATERS

very turbid waters supplied in small quantities (50-500 Jackson Candle Units and 10-100 gal/hr). A promising application is the treatment of potable water supplies for company-size military installations (100-200 men), particularly overseas bases. The foam separation process is initiated by the addition to the raw water of a cationic surfactant (quaternary ammonium salt) which is adsorbed at the surfaces of the particles. The specific surfactant used in this study (cetyldimethylbenzylammonium chloride) has Food and Drug Administration approval for human ingestion of up to 40 mg/day as throat lozenges. The organophilic particles are then floated to the water surface by attachment to diffused or precipitated air bubbles and are carried into a foam phase rising above the water surface. The foam is highly concentrated in both surfactant and particulates and the water is clarified. The clarified water may then be pumped through a column of powdered active carbon to remove trace organics and (although not required) to remove the residual surfactant concentration. The